From the prior art it is known to overcome radio barriers in such a way that an antenna of the first device is extended by a cable extension so that it can be arranged on the other side of the radio barrier (e.g., a shielding housing). Furthermore, active Bluetooth or WLAN repeaters, sometimes also with intermediate networks, are also known that are not suitable for many applications, however, due to the installation space, the costs, and the necessary power supply.
U.S. Pat. No. 8,462,062 B2 shows a passive wireless repeater that is mounted on the side wall of a container. The repeater includes a first antenna on one side of the side wall, a second antenna on an opposite side of the side wall, and an electrical connection between the first antenna and the second antenna.
From the published EP 2 720 313 A1, a device is known for forwarding radio signals through a metal wall. Similar devices are to be found in U.S. Pat. No. 7,629,943 B2, US 2003/0214774 A1, and JP H04-74 025 A.